Lightly grease the springform or loose-bottom cake tin and line the base of it with baking paper. Set aside.
Crush the biscuits (use food processor or do it by hand by placing the biscuits into a zip-lock style bag and use the rolling pin to crush them) into small crumbs and mix them well with melted butter. Transfer this mixture into prepared baking tin and press firmly towards the the bottom of the tin to make an even base ( I like to use the back of my measuring cup to do it, but you can also use the back of the spoon or the side of the glass). Place it in the fridge to chill, while you prepare the filling.
Place the cream cheese and the icing sugar in a large bowl and using an electric mixer, whisk it on medium speed until combined. Add the cream, vanilla and Baileys and continue to mix until all the ingredients are well incorporated and you have smooth, thick and creamy batter. Lastly, reserve about 2 tablespoons of the grated chocolate, then fold the rest of it into the cream cheese mixture.
Remove the cheesecake base from the fridge and pour the cheesecake batter on top of it. Spread it evenly, then smooth out the top with spatula or a palette knife. Place the cheesecake in the fridge for at least 4 hours, or ideally, overnight.
To make the topping:
Place the cream, icing sugar and 1 tablespoon of Baileys in a large bowl and using an electric mixer, whip until soft peaks. Transfer the whipped cream into a piping bag fitted with the nozzle.
Remove the cheesecake from the fridge, and pipe the whipped cream on top of it. Sprinkle the top of the cheesecake with some grated chocolate and decorate it with Baileys truffles sliced in half (if using). Slice and enjoy!
Make sure the cheesecake ingredients are at room temperature before starting the recipe.
Do not overbeat the cream for the topping, as it will split and curdle. Whip it until soft peaks only!
Store any leftover cheesecake in the airtight container in the fridge for up to 3 days.
The cheesecake can be frozen for up to three months. Thaw it in the fridge overnight.